1. Field of the Invention
The present invention relates to a smart speed control, power-saving and noise-reduction paper shredder, and more particularly to a paper shredder having a knife or another cutting or tearing component to divide pieces of paper into shreds.
2. Description of the Related Art
Conventional paper shredder generally comes with a single rotation speed, a constant number of pieces of shredding paper, and a constant power for the operation of an electric machine.
If the paper shredder has one or two piece of paper remained or rotates idly, the electric machine will rotate at a higher rotation speed, make a louder noise, and consume more electric power. In a paper shredder electric machine as disclosed in P.R.C. Pat. No. 201113903Y, a speed control system is provided for adjusting the speed of the electric machine manually. In a paper shredder as disclosed in P.R.C. Pat. No. 201181926Y, an automatic gear control system detects the rotating speed of the electric machine and maintains the rotating speed of the electric machine automatically by optical controls, so as to overcome the aforementioned issues of the conventional paper shredder. However, both of the issued patents control the speed of the electric machine by changing the number of coils of the electric machine, and thus these patented technologies can be applied for AC electric machines only, but not for DC electric machines.